This is a representation of the rock types that occur at or near the surface on the Isle of Man. Most of the rocks are in fact covered by a thin layer of soil so that the map is an interpretation – the geology is extrapolated from areas where the rocks are exposed such as at the coast or in quarries. A large part of the Island is composed of a suite of rocks collectively known as theManx Group. These were originally sediments deposited on the sea bed 490-470 million years ago.
